Sensitive control mechanism



y 6, 1946. H. ERNST 2,404,121

SENS ITIVE CONTROL MECHANISM Filed Aug. 2, 1933 6 Sheets-Sheet 1 3 mm f/ /vs ERNST July 16, 1946.

H. ERNST SENSITIVE CONTROL MECHANISM Filed Aug. 2, 1 933 268 6 Sheets-Sheet 2 July 16, 1946.

H. ERNST SENS I'I'IVE CONTROL MECHANISM Filed Aug. 2, 1933 6 Sheets-Sheet 3 FJyB' July 16, 1946. H. ERNST SENS ITIVE CONTROL MECHANISM Filed Aug. 2, 1933 s Sheets-Sheet 4 36 i 88 {Ir/ T 45 ga I a 95 mi? 94 H. ERNST SENSI'VI'IVE CONTROL MECHANISM 6 Sheets-Sheet 5 Filed Aug. 2, 1933 July 16, 1946.1

July 16, 1946. H. ERNST 2,404,127

SENSITIVE CONTROL MECHANISM Filed Aug. 2, 1933 e Sheefs-Sheet e I if 2 L a6 a GEM/W5 Patented July 16, 1946 OFFICE SENSITIVE CONTROL MECHANISM Hans Ernst, Cincinnati Cincinnati, Ohio, assignor to The Milling Machine Co.,

Cincinnati,

()hio, a corporation of Ohio Application August 2, 1933, Serial No. 683,330

70 Claims.

This invention relates to improvements in sensitive control mechanism and particularly to mechanism of this character which may be advantageously employed in connection with the control of the training or elevation of naval guns or proper determination of azimuth and elevation in connection with anti-aircraft or coast defense artillery weapons.

One of the principal objects of the present invention is the provision of a control mechanism of extreme sensitivity and accuracy, particularly intended for use in connection with or substitution for the turret and gun control mechanisms at present utilized by the land and naval forces.

Another object of the present invention is the provision of a mechanism readily adaptable to and utilizable in conjunction with control mechanisms of the types now employed and which will render possible elimination of manual control of guns and co-ordination of self-synchronous signaling motors and indicators, thus eliminating the inaccuracies due to the human element, reducing the crew required for operation of a given piece or battery and insuring maximum accuracy of gun setting comparable with the instrument determined desired position therefore.

A further object of the present invention is the provision of a novel and improved form 01" power control mechanism in which the original determinator of direction and amount of adjustment 5 shall be subject to so little friction or opposition to movement as to be capable of operation by and as a part of a standard type self-synchronizing electric motor unit of either the stationary or movable pointer system and which in any event shall accurately transmit to the heavy drive mechanism necessary for attaining the adjustments the exact positional Variation indicated and efiected by the minute power transmitting electrical signalin system.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings in which the principles of my invention have been diagrammatically indicated in conjunction with selected structural units particularly adapted for carrying out the principle thereof, but it Will be understood that any modifications may be made in the specific structural details chosen for purposes of illustration, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

Figure 1 represents a diagrammatic view indicating the general relationship of the parts in an installation of the present invention for control of the trainin of a naval gun turret and the elevational adjustment of the guns within the turret. 1 Figure 2 is a detailed diagrammatic, view ofthe high speed approximate adjustment and r, the minute or more accurate final adjusting circuits and the self-synchronous devices as utilized for. effecting adjustment of the piece either for azimuth or for elevation. r f

Figure 3 is a plan view of one form of the pressure difierentiator for the hydraulic; amplification control circuit. o I Figure 4 is a section through thepump.adjustment control motor as on the line 4-4 of Figure 2. Figure 5 is a section on the line 55 of Figure .3. Figure 6 is a section on the line 6-6 of Figure5. Figure 7 is a section on the line l! of Figure 4. Figure 8 is a section through a self-synchronous motor unit havin a rotatable fields 1 Figure 9 is a modified form of one portion. of the control circuit shown in Figure, 2. 1

Figure 10 is a modified form of manual control mechanism. t v Figure v11 is a sectional view of the gun elevating mechanism shown in Figure 1.

Figure 12 is a detailed view of the elevating I mechanism taken on the line |2-l2r of Figure 1. Figure .13 is a modified form of the pressure differentiator shown in Figure 3 with a self-sym chronous motor unit of the stationaryfield type. Figure 14 is a diagram showing the connec tions to the device shown in Figure 13.

Figure 15 is an end View of the control dials as viewed on the line l5l5 of Figure 13;

Figure 16 is an end view of the control dials as viewed on the line l6l6 of Figure 8.

Figure 17 is a detail section of the rate and direction determinator of the pump-motel power unit.

Figure 18 is a detail end view of oneof theports of the pressure difierentiator as viewed onthe line l8-l8.of Figure 5.

Figure 19 is a section on the line Ill-I 9 of Figure 2.

Figure 19a is a section on the line I lid-I911 of Figure 19. i g a Figure 20 is a modified form of pressure differentiator.

Figure '21 is a diagrammatic view illustrating principles involved in this one of the hydraulic invention. 1 t

Figure 22 is a simplified diagram of the ele-,

ments involved in the hydraulic amplification system. r

Figure 23 is an expanded sectional View of the dilierentiator disc of Figure 20 showing the profiling of the opposite faces thereof.

Figure 24 is a section on the line 24-24 of Figure 9.

It is conventional gunnery practice among combat forces to depend upon the intelligence and physical force of the gunner in actually effecting the angular position of the gun in its various planes of adjustment in accordance with the signals communicated to him from the fire control stations. With heavy, long-range pieces, such practice may consume valuable time under conditions of stress or emergency; and furthermore since the human element enters into the final setting, the possibility of inaccuracy in the setting is ever present.

This invention contemplates the use of an interponent motive power means which may be substituted for the intelligence and physical force of the gunner and which is so organized that it will be responsive on the one hand to signals received over a communication system from the fire control station which now imparts the range settings to the gunner, and which, on the other hand, has sufficient power to effect the actual physical adjustment of the gun in an accurate and expeditious manner.

In naval gunnery, particularly, there are two different systems of communicating range settings from the remote fire control station to the gun, and indicating their completion, one of which is known as the fixed pointer'system, and the other as the movable pointer system. In the first system, a fixed pointer such as l8], Figure 16, is established in convenient position relative to the gun mount together with a movable pointer carried by disc I80 operatively connected by remote control means to the fire control station, at which station suitable means are established for sighting the target and for computing the range which is communicated to the gunner through movement of the pointer I30. As this pointer is rotated by the control station through an indicated angle equal to the desired angular movement of the piece, the gunner actually moves the gun, which in turn will react in a definite manner on the movable pointer at his station to rotate the same in an opposite direction to maintain the same in an alignment with the'fixed pointer, and so long as this alignment is maintained, the gun is in the position desired by the control station.

In the other system of communication two movable pointers are utilized, the first one 52, Figure 15, being under the direction of and moved by the fire control station to indicate or signal the angular adjustment desired, and the second one '53 being moved by the gun in response to movement imparted thereto by the gunner, so that the gunners duties are reduced to the simple proposition of so moving the gun as to maintain the two movable pointers in alignment.

It will thus be seen that in either case there are two relatively movable pointers; that relative movement or separation between them is effected by the fire control station to communicate or signal an angular movement and that realignment of the pointers is effected by movement of the gun through the signalled angle.

A common form of means for communicating motion to the pointer from the fire control station consists of two self-synchronous electric motor devices, of known form, one of which is at the fire control station and may be termed the transmitter and the other at the gun mount which may be termed the receiver. These devices are electrically interconnected, in the manner more particularly shown in Figure 2, whereby any angular movement of one rotor will be imparted to the other rotor. The reference numeral 25 indicates the self-synchronous transmitter at the fire control station, the rotor 42 of which is connected by shaft 26 to the fire control unit 21. The stator 28 of the transmitter may be made up of three legs or poles 29, 30 and 3| which are Y-connected at one end and separately connected at the other to leads 29', 30 and 3| which extend from the fire control station to the receiver motor at the gun mount. In the construction shown in Figure 2, the transmitter 25 has a fixed field, or stator, while the receiver motor 32 at the gun mount has a rotatable field. Therefore in this case the leads 29', 3G and 3| terminate in brushes 33, 34 and 35 riding respectively on the collector rings 36, 31 and 38, these rings being connected in turn respectively to the three field coils 39, 40 and 4| which are also Y-connected.

In the construction shown in Figures 13 and 14, however, both the transmitter and receiver fields are fixed, and thus the leads 29, 30, and 3| are directly connected respectively to the field coils 39, 40 and 4|. In each case the rotor 42 is connected by means of collector rings 43 and 44, and brushes 45, and 46, to a pair of leads 4'! and 48 constituting a rotor-excitation circuit. The leads 4! and 48 are connected with a suitable source of single phase alternating current and serve to supply current for exciting the rotors. The rotor 49 of the receiver 32 is similarly connected by a pair of leads 50 and 5| to a similar excitation circuit which may be the same power lines 41 and 48. The operation of the device is such that when the excitation circuit is closed, an alternating current voltage is impressed on the rotors of both the transmitter and receiver. Since the receiver rotor is free to turn, it assumes a position similar to that of the transmitter rotor. As the transmitter rotor is turned, the receiver rotor follows at the same speed and in the same direction. The reason for this selfsynchronous action is that the single phase current in the rotors induces voltages in the. three legs of each field system. These three voltages are unequal in magnitude and vary with the position of the rotor. When the two rotors are in exactly corresponding positions, the voltages induced in the transmitter field are equal and 0pposite to those induced in the receiver field; that is, they are balanced, so that no current flows in either field winding.

If, however, the transmitter rotor is moved from the original position, the induced voltages are no longer equal and opposite, and current flows in the field windings. This current flow sets up a torque tending'to turn the receiver rotor to the synchronous position relative to its field. This position corresponds to the new position of the transmitter rotor relative to its field.

Thus, if the transmitter rotor is moved, whether mechanically by gears or manually by an operator for a signaling or control operation, the receiver rotor immediately assumes a similar position relative to its field.

If now, the rotor 39 is operatively connected to a pointer such as 52, as more particularlyshown in Figures 13 and 15, it will be seen that any movement imparted to the shaft 26 by the fire control unit will eiiect rotation of the pointer 52.

Further, if a second pointer, such as 53, is operatively connected to a gun, so as to be responsive to angular movement thereof and to move simultaneously through the same indicated angle that the gun moves, it will be apparent that by keeping the two pointers in alignment the angular position of the gun will always be in accordance with the position desired by the fire control station. The rotor 49 and pointer 52 thus constitute a receiver of the communication system through which the gunner receives his instructions for changing the azimuth or elevation of the gun.

As previously pointed out, this invention contemplates the substitution of an organized power control means for the intelligence and physical effort of the gunner, which control means may be connected on the one hand to the receiver of the communication system for response to signals received thereby, and, on the other hand, to the gun adjusting mechanism, in such a manner that upon reception of a signal as witnessed by the slightest movement of a pointer, the required gun adjustment. will immediately be power efiected; and the fact that this adjustment has been made will be evidenced by a return signal from the gun in the form of pointer movement depending upon the pointer system being utilized.

The chief elements of this sensitive power control mechanism comprise a large motive power unit capable of developing the necessary torque to perform the physical work of translating or elevating the gun, and an hydraulic control system operatively coupling the receiver of the communication or signaling system for control of the power unit and capable of starting, stopping, and determining the rate and direction of movement thereof and thereby of the gun. The actual connection to the receiver rotor 49 is by an hydraulic amplification system of the pressure differential type comprising a part which is very light and sensitive to movement and may therefore be di rectly connected to the receiver rotor for movement thereby without imposing any appreciable load on it, or in any way acting to retard its free movement. It is obvious that for complete control of the gun in a given plane, the power unit must be capable of being started and stopped, as well as subject to reversal and change of rate in either direction, and that all of these functions should preferably be combined for control 'by a single unit for simplicity.

A power unit which best satisfies these requirements is a hydraulic variable speed transmission gear composed of a variable speed pump unit, a motor unit and a single control member for obtaining all of the various functional adjustments. Such hydraulic devices are well known and therefore are only conventionally illustrated. The reference numeral 54 in Figure 2 indicates a known form of hydraulic variable speed transmission gear, the operative principle of which is the same as that shown in Patent No. 924,787 issued to R. Janney, having a pump end 55 and 2 motor end 56. The pump end comprises a rotatable shaft 5'! which may be continuously rotated by suitable means such as an electric motor 58. A cylinder barrel 59 is keyed to the shaft 51 for rotation therewith and has a plurality of cylinders 60 formed therein. each containing a reciprocable piston 6|. The pistons are connected by piston rods 62 to a swash plate 53 which is supported by the shaft 57 not only for rotation therewith but also for movement about an axis 64 at right angles to the axis of the shaft. An angle box 65, Figure 17, is trunnioned behind the swash plate 53 for movement about an axis coaxially with the axis 54 for varying the angular position of the swash plate relative to the plane of the cylinder block 59 so that upon rotation of the shaft 5'! the pistons 6| will be caused to reciprocate in the cylinders 60. It will be evident that when the swash plate 63 is parallel to the cylinder block 59 or in other-words in a position as shown in Figure 2, that rotation of the shaft 51 will not impart any reciprocating movement to the pistons 6i, and therefore n fluid will be pumped to the motor unit and the parts will be at rest except for the continuous rotation by the electric motor.

The motor unit is similar to the pump unit in that it has a cylinder block '66 in which is formed a plurality of cylinders 6'! similar to the cylinders Bl! and each cylinder has a piston 68 operatively connected by a piston rod 69 to a second swash plate 19. This swash plate is supported upon an output shaft ll, but usually at a predetermined angle thereto, all adjustment being taken care of in the pump unit. A medial plate 12 separates :le cylinder blocks and has a pair of arcuate shaped openings 13, Figure 24, one of which serves to deliver fluid under pressure from the pump cylinders to the motor cylinders to cause outward movement of the contained pistons, and the other to return fluid to the pump, from the motor cylinders during the inward movement of their pistons; the function of these openings being reversed upon reverse operation of the pump. 7

When the plate 63 is adjusted counterclockwise from the position shown in Figure 2, the

" pump will deliver fluid to the motor in such a direction as to cause rotation of the shaft 'H in one direction, while if it is adjusted counterclockwise, the direction of rotation will be reversed. Also, the angle of adjustment of the swash plate 53 determines the speed of rotation of the motor unit, a slight angular adjustment imparting a slow rate of speed, while a'large angular adjustment will impart a high rate of speed. 5

The angle block is provided with an adjustingarm which may be actuated directly by areciprocating member through a piston and cylinder, but for accurate and minute adjustment,it is preferable that it be connected by means of a screw and nut to its actuator in the manner shown in Figure 17. The arm 12 may be connected to a threaded member 13 passing through a nut member 14 secured to the end of a rotatable shaft 15. The pitch of the screw and nut may be such that a partial rotation of the shaft'75 to either side of a'central position will effect the complete range of adjustment of the swash plate.

The manner of with a gun mount is assembling this power unit more particularly illustrated in Figure 1 which shows a typical form of turret such as used on naval vessels. The gun 16 is pivotally mounted on trunnions at 1'! in the turret for elevation and the turret 78 is supported as by a plurality of tapered rollers 19 on the hull structure 80 of the vessel for rotation in a horizontal plane to train the gun. The training mechanism usually comprises an internal gear 8|, which is fixed to the structure 80-, and has meshing therewith a large pinion gear 82 supported on the end of the depending rotatable shaft 83 carried by the turret.

Elevation of the gun may be effected by a mechanism such as shown in Figures 11 and 12, comprising a large screw at 85 to the breach end of B4, pivotally connected the gun a considerable distance from the trunnion 11. The screw 84 passes through a nut 86, which. is rotatably mounted in pivoted bracket 81, and has integrally secured to one end a bevel pinion 88 meshing with a bevel gear 89. The bracket 81 is trunioned at 90 and 3| in a bifurcated fixed support 92. The bevel gear 89 is secured to the end of a shaft 93 which passes through the center of one of the trunnions and has secured to the outer end a worm gear 04 meshing with a worm 95. The worm 95 is secured to a shaft 96 which is connected through bevel gearing 91 to a horizontal operating shaft 98. It Will now be seen that rotation of the shaft 98 will cause through theinterconnecting mechanism, rotation of the bevel gear 88 and its integral nut 86 and thereby axial movement of the screw 84. This axial movement will cause elevation or depression of the gun, and as the same moves upward or downward, the bracket 81 will automatically angularly adjust itself about its trunnions. The shaft 83 of the training mechanism is also connected by a worm wheel 99 and a Worm I to a horizontal driving shaft I0 I In the past each of these shafts 98 and IOI have been operatively connected to manual control means for operation by the gunner. By the present invention, each of these shafts is provided with a power unit 54 operatively connected thereto and an independently operable automatic control system for each unit. In other words, there may be two separate independent automatic control systems, one of which may be a duplicateof the other and therefore only one will be described. For the sake of economy, or simplicity of construction, however, where functional requirements permit, certain of the elements may be common to both systems. Furthermore, if the fire control unit is of such a construction that it provides a master controller for both systems, it is obvious that their independence will apply to their operative functions only.

Rotation of the power unit control shaft 15 is effected by a hydraulic motor I02 which may comprise, as shown in Figures 4 and '7, a plurality of pistons I03 carrying anti-frictionally mounted rollers I04 on the inner end thereof engaging a multiple lobe cam I05 carried by a rotatable shaft I06. Although a rotatable type motor has been shown, it is obvious that a double acting cylinder and piston type motor could be used, either to cause a rotation of the pump control shaft as by means of a rack and pinion, or else to actuate the swash plate 63 directly, as heretofore mentioned. In either case two pipes I01 and I08 supply fluid to the motor and are so connected thereto that when pressure is supplied through pipe I01, and pipe I08 is connectec" to exhaust, the motor will cause movement of the swash plate 63 in one direction, and when pressure is supplied through pipe I08, and pipe I01 is connected to exhaust, the motor will cause movement of the swash plate in the opposite direction; while if pipes I01 and I08 are both kept under an equal pressure, the motor will stop and be held in any given angular position. A valve mechanism has been provided for controlling the flow in these pipes, and although two valves, such as I09 and 2M, are shown in Figure 2, in its simplest form and for limited purposes only, invention may be practiced by the one valve.

This valve may comprise a fixed sleeve I09, as more particularly shown in Figures 2 and 5, having a reciprocable plunger I I0 contained therein.

use of only the The sleeve has an annular pressure groove III formed therein to which is connected the pressure channel II2, the pressure fluid being supplied by a pump I I3. A reservoir tank I I4 is provided from which fluid is withdrawn through a pipe H5 by the pump II3. In order to maintain constant pressure in the pump delivery line- I I2, a relief valve H6 is connected thereto by the branch line II1. A plunger H3 is reciprocably mounted in the valve and. has a spool H9 which controls the flow through the exhaust port I20. The pressure in line H1 is connected by anaxial bore I2l in the plunger to the end- I22 of the valve housing to normally force the valve in a direction to increase the volume of the escaping fiow. This movement is opposed, however, by a spring j23, the opposition of which may be adjusted by the set screw I24. By this means the spool I I9 may be adjusted and maintained to prevent variation of pressure in line II2.

The plunger I It! has a spool I25 formed thereon which may be of sufficient width to close the radial holes formed in the bottom of the groove III and thereby prevent flow to either annular groove I26 0r I21 to which the pressural control channels E08 and I01 are connected. Flanking grooves I23 and I21 are another pair of grooves I28 and I29 which may be connected by branch lines I30 and I3I to acommon return line. It will now be seen that if the plunger I 50 is moved from the position shown in Figure 2 toward the left, that pressure will new from channel 2' to channel I01 and that the channel I08 will be connected to the exhaust channel I30; or if moved to the right the channel II2' will be connected to channel I00 and channel I01 will be connected to the exhaust line I3I. Tnus by movement of the valve plunger III} to the right or left the direction of rotation of the shaft 15 can be controlled, and furthermore that the rate of this rotation may be determined by the amount that the plunger H0 is moved off center,

The shifting of this valve plunger is controlled through a relay in the form of a sensitive hydraulic amplification system, which is responsive to movement of the rotor 49 on the one hand which, as previously explained, is the receiver of the communication system; and to the movement of the gun on the other hand. The hydraulic amplification system comprises a means for magnifying the movement and power output of the rotor so that a very slight weak movement thereof will effect sufficient opening of the valve IIO to develop a strong force for controlling operation of the hydraulic variable speed transmission gear. The valve plunger H0 is moved by a pair of piston portions I33 and I34 formed on opposite ends of the plunger, and actual movement is effected by unbalancing the opposing forces on the pistons by a pressure difierentiator I35 which may be in the form of a disc rotatable relative to a pair of ports or jets I36 and I31 which are respectively connected by channels I38 and I39 to opposite ends of the valve plunger I I0.

When a pressure differential is .created by the disc I35, the plunger H0 will be moved and will continue to move until a pressure equilibrating means has re-equalized the pressures on opposite ends of the plunger. Fluid for this purpose is continuously supplied from channel II2 through branch lines I40 and MI which are respectively connected to annular groovesIAZ and I43 formed in the sleeve I00. Carried by and movable with the valve plunger I I0 are variable resistance por- 9 tions which may be in the form of tapered spools I44 and I45 associated with the elongated radial ports formed on the bottoms of grooves I42 and I43. These spools are so dimensioned with respect to the ports that when the plunger III! is in its mid-position, the resistances to escape of fluid from the grooves I42 and I43 are exactly equal.

Holes I46 and I4! are drilled in oppositeends of the plunger and connected by radially drilled holes I48 to the annular space adjacent to: the spools I44 and I45. The fluid from the channel H2 is thus connected through the branch lines I40 and MI, the hydraulic resistances formed by the spools I44 and I45, and the drilled holes in opposite ends of the plunger to the cylinder portions formed at opposite ends of the sleeve I09. The fluid then flows from these cylinder portions through channels I38 and I39 to be discharged at the ports I35 and I3? against the periphery of the disc I35.

This disc has a circular peripheral portion extending from the point I49 counterclockwise to the point I59, and of a radius equal to the distance from the center I 5I of the disc to the faces of the ports I35 and I31 minus a few thousandths of an inch clearance. The included angle measclear that the total resistance of the path from ured from the point I49 counterclockwise to the point I50 is a few degrees less than 180 degrees. The disc has also a concentric peripheral'portion extending from the point I5I counterclockwise to the point I52 which has a radius of a few thousandths less than the radius of the portion I4'II5il. The included angle measured from the point I5I counterclockwise to the point I52 is likewise only slightly less than 180 degrees. The points I49 and I52 as well as the points I55 and I5I' are connected by a profiled portion which has a continually decreasing radius so as to provide a resistance to the flow of fluid through the ports I36 and I3! which will vary with the angular position of the disc. When the angular position of the disc is such that the spaces between the ports and the respective profiled positions are equal, as shown in Figure 2, the resistance to flow of fluid therethrough will likewise be equal.

The disc I35 is mounted on the shaft I53 which is co -axial with rotor 49 and permanently connected therewith so that the slightest movement thereof will cause rotation of the disc. The fluid discharging from the ports I35 and I31 is collected in the chamber I54 formed in the bottom of the housing I55 and discharged freely through a suitable channel I56 to the reservoir I I4.

From the foregoing it will be evident that, if the valve plunger H0 and the disc I35 are both in their respective mid-positions, there will be two parallel paths of equal total resistance for the fluid to traverse from the supply channel II2 to the chamber I54. Thus the quantity of fluid flowing through these two paths will be equal, and as the resistances at the ports I35 and I3! are themselves equal, the pressures in the channels I 38 and 35 will also be equal, and thevalve plunger Hi3 will thus tend to remain in its'midposition.

If we now assume that the disc I35 is rotated through a small angle in a counterclockwise direction, the resistance to outflow of fluid from the port I31 will be increased while the resistance at the port I35 will be decreased. If the plunger IIIl could meanwhile be held in its mid-position so as to retain the initial equal values of the resistances to flow past the spools I44 and I45, it is the constant pressure channel IIZ through the port I 31 will be higher than that through the port endin s t qu ntit 9 l fiow'ifig throughI-SIS will be higher than-through I3I. .B i1t this';higher quantity also flowsthrouglilthe resistanceformed by the spool museums lower quantityflows through the resistance formed by the spool I45, and "sths resistancesar bihg maintained. qua 1 a above statedLQtHen the pres;

sure drop past the spool I44 will be lfiglierlthan that past the spool I4 Therefore, 'asthe pressure in the channel 'I I 2 is maintained at. a constant value, the pressure in the channel I39 will be higher than that in the channel I38, and so there will be a pressure differential acting upon the valve plunger II'ii tending to move it toward he-left; I n no h ld b t free o mo e s. i a iu y t oasa it will be-moved to the left by this pressure iff ential flovernenttoward the left, how

ever, will decrease the value of the resistance past the spool I44, and increase the resistance past the spool I45. The decrease and increase of these resistances will respectively decreaseland increasehe-t tal re i nc of e.iwe re e fiQ i e h from-channel i IZ to chamber I54, therebyfure: ncrea d d r a th r sp flows therethrough. Increase and decrease, respectiveiy, oi the now through the resistances past the ports I36 and I31 will cause a respective rise and fall in the pressure drop across. these ports, and consequently a rise and fall, respectively, in the pressures in the channels I38 and I39. This rise and fall, it will be noted, is in the opposite direction to the change in pressure pro-- duced by the movement of the disc I35, thus it is evident that continued movement of the plunger I ill to the left will. eventually bring about a i e-equalization of pressurein these channels and .thus a cessationof movement of the plunger. With this device, therefore, every increment of movement of the disc I 35 willcause a corresponding increment of movement of the plunger III]. As the increment of movement of the latter is limited in each. case to the amount required to bring abouts r-fequali'aation of pressure upon its ends an'dthis'in t'ur'nis determined-by the, change in resistance past the spools, I44 and I45, any desired relation between these increments, 'i. 42., any desired amplification, can be obtained by providing the proper rate of change of resistance with motionof the spools I44 and I45 in relation to the rate of change of resistance by motion of the disc I35. I

The above described principle of operation will be more readily understood .by reference. to Figurel22 whichis a diagrammatic representation of the hydraulic resistances andicontrofl elements involved a'ndarrang'ed in Simple form tofacilitate mathematical: analysis of the underlying relatio'hs. f

lnzthis'figur'e Rb and Rm. respectivelyqrepresent the instantaneousvalues of the hydraulic resistance's betweenthe .por'ts I36 and :I37 and the ad.- jacent profiled portions of the. disc I35, while 'Rv and Rw respectively represent the instantaneous values oitheresistances formed bythe spools. I44 and 145.; Q'b;Qm, Qv. and Qw'represent the quantities, or rates of. flow, [through theresistances RaiRm, Rv,,.and Rw; P1 isthe pressure in thewsupmy chan el i r zand a e-p es u s he ha s a d I 3..-an P the-p surein-fih collecting chamber I54, (usually atmospheric pressure) The link 3B5 illustrates the mechaniwe now assume that this plunger is r the value of the resistance itself or P=QR. Thus 1 But if Pi-P2 is not equal to P -P2, then P2 and P3 will themselves be unequal and thus the piston portions I33 and I34 will be moved toward the end acted upon by the lower pressure. Such movement, however, will cause a change in the values of the resistances Rv and Rw in such a direction as to make P2 equal to P3.

' When P2 is equal to P3, P1P2 will be equal to -P1P3, and P2P4 must then be equal to P3-P4, therefore QwRw must equal QvRv, and QmRm must equal QbRb. Furthermore, when pistons- I33 and I34 are stationary, Qw must equal Qm, and Qv must equal Qb, thus we may write:

whenever P2=P3, that is, whenever the system is in equilibrium.

Thus any movement of the disc I35, which causes a change in the resistance ratio it Rm will bring about a movement of the valve plunger I II] which will continue until the resistances past the spools I44 and I45 will have assumed such values that the ratio m will be equal to the new value of the ratio It will thus be seen that this device is in effect a self-regulating hydraulic Wheatstone bridge, similar in principle to that disclosed in co-pending application, Serial #490,154, filed October 21, 1930, by Hans Ernst, et al., Figure 10 of which application is reproduced here as Figure 21 for the purposes of comparison with Figure 22; the only change made from the original is that the original reference numerals have been primed for obvious reasons.

In Figure 21 it will be seen that there is a pressurepump which delivers fluid at a pressure P1 totwubranches 4' and 5' which include the variable resistances R'w and R'v equivalent to the diagrammatically illustrated resistances of Figure 22 and comprising in the case of R'w, a variable work resistance, and in the case of R'v a variable compensating hydraulic resistance.

and II respectively to the complementally variable hydraulic resistances R'm and Rb corresponding to resistances Rm and Rb of Figure 22 which combine in a common return line I3 similar to the common return line I56, and having a pressure P4. It will also be noted that channels 8 and II have operating branches I4 and I5 respectively which are responsive to the equal or unequal pressures P2 and P3 existing respectively in channels 8' and II.

That the work resistanceris in effect an hydraulic resistance may be shown in the following way. In Figure 21, the opposition to free movement of the work piston connected by the rod 6' to the slide 1' is provided by the cutter C acting against the work piece W. For a given total opposition to movement, and a given equivalent piston area, there will be a given unit pressure difference across the piston. For a given equivalent quantity, or rate of flow Qw, the equivalent resistance may be expressed in terms of reaction to unit flow as which is the resistance Rw, and therefore directly comparable to the hydraulic resistance Rw of Figure 22.

The system in Figure 21 is thus similar to 1 that in Figure 22 and therefore the same equations must apply, that is, that J mes R,,,' R',,

whenever P2=P3.

Any movement of the valve spool relative to the ports 9' and I2 from its central position will efiect a complementary change in the value of the resistances R'm and R's. If moved in a direction to make R'm R'b then there will be a fall in P3-P4 and a rise in Pz-P4 which means that P2 P3 which inequality will be communicated to the operative branches I4 and I5 to effect a reproportioning of the in'tial resistances R'w and Rv to thereby re-equalize pressures P2 and P3. In the construction shown in Figure 21 this reproportioning or change is all effected in the resistance R'v while in Figure 22 the change is efiected by complementally changing resistances Rw, Rv. The efiect is the same because in either case we seek to make the rati Therefore, if we make Rm Rb, we decrease the value of the fraction or ratio A corresponding change may be brought about in the fraction in two ways: (1) by decreasing only the value of Rv, or (2) partially decreasing Rv and partially changed to equal These resistances are connected by channels 8 F5 and by the same means, that is a-pair of operating branches responsive to pressure changes in the main channels operating on opposed piston elements, operatively connected to change the value of the ratio of the initial resistances in the respective flow paths, which change will continue until the ratios are equal because at that time the pressures P2, P3 are themselves equal.

From the foregoing it will be evident that with the construction shown in Fig. 2 (diagrammatically illustrated in Figure 22) by properly proportioning the values of the hydraulic resistances Rb, Rm, Rv and Rw, and their rate of change of resistance with respect to movement of their controlling means, a highly sensitive remote control system is obtained, in which a secondary or relay member, such as the Valve plunger 1 I0, may be incrementally progressed by incremental movement of a sensitive primary member, such as the disc I35, without any mechanical connection between them.

The operation of the device as described thus far is as follows: referring to Figure 2, the shaft 26 will be rotated by the fire control unit which in turn will cause rotation of the rotor of the syn-- chronous generator or transmitter 25 which by means of electrical phenomena will cause a similar angular movement of the receiver rotor 49. The shaft I 53, which is connected for rotation with the rotor 49, will cause angular displacement of the disc I35 and thereby create a pressure differential between channels I 38 and I39 which will be communicated to opposite ends of the plunger H0. sure will cause the plunger to move in the direction of the lower pressure and to continue moving until the pressure has been re-equalized, as previously described. Since the resistance spools I44 and I45 may be made of any length and thus provide any desired rate of change of resistance, it will be apparent that the length of plunger movement may be independent of theangular movement of the disc I35 which thus" makes it possible to magnify a very slight movement of the disc I35 into a large movement of the plunger I II].

When the plunger I I is moved to the left, fluid will flow in line I83 and line I31 will be 'connected to exhaust whereby the motor I02 will continue to rotate until the plunger III) has been moved back to a central position. The rate of rotation will furthermore depend on the amount of displacement of the plungers. Rotation of the motor I02 will cause an angular displacement of the swash plate 63 and thereby initiate and continue to increase the displacement of the pump which will thus supply fluid to the connected motor unit and efiect rotation of the shaft 1I. As a matter of practical operation, the shaft H is connected to the shaft IBI through a shiftable clutch member I51 which is splined on the shaft IDI for movement by the manual control lever I58. Clutch teeth I59 on one face of the clutch are adapted to engage clutch teeth on end of shaft "II for power rotation of the shaft Illi. Clutch teeth I65) on the opposite face of the clutch are adapted to engage similar clutch teeth on the face of a large bevel gear ItI which is normally free to rotate, but intended for manual rotation of shaft IOI by means of bevel pinion I61 and hand wheel I58 in case of emergency.

It will thus be seen that a means has been provided whereby movement of a control shaft such as 26 at a remote station may be transmitted to the gun and impart movement to the gun adjusting mechanism.

The actual construction of one for-m of pressure This unbalancing of pres- 14 differentiator is shown in Figures 5 and Brand comprises the housing I having an upper rectangular shaped space IE2 in which is rotated the disc I35. This disc is supported for rotation on anti-friction bearing I 53 to insure easy movement thereof and prevent any frictionalload on the rotor '49. The disc has a peripheral flange "54- which is of sufiicient width as shown in Figure I8 to insure against the free lateral escape of fluid from the ports I36 and I31 and permit proper operation of the device. The ports are formed in shoulderedmembersw "ch are longitudinally divided as shown in Figures -5 and '18 toform two halves I35 and I66 which are milled at the end to form a long narrow slot which forms the ports I 36 and I31. sembled in a sleeve-I61 and held tightly therein by the threaded plug member I 68. An axial Ibore IE9 is formed in the shouldered members and terminates in the elongated port at one end thereof; The sleeve IE1 is slidably mounted in a bore I 10 which is formed in the housing and has a radial port I1I which communicates at one end with the channel I39 and at the other end with 'a radial bore I12 in the shouldered member comm-unicating with the axial bore I69. A set screw I 13 engages a keyway I14 formed in the periphery of the sleeve to prevent the same from rotating. The sleeve I10 is axially adjusted toward and from the periphery of the disc by means of a screw I15 which isthreaded in the plug member I 68 and which passes freely through a hole I16 in a second adjustable member I11. member is adjusted to the desired position and then the screw I 15 is tightened to draw the sleeve back into clamping engagement with the member I11. This makes it possible to adjust the distance between the periphery of the disc and the face of the port, which distance is approximately fiVe-thousandths' of an inch when the disc is in its normal position shown in Figure 2. The peripheral portions between the points I58 and I51, as well as between the points I49 and I52, are so profiled as to increase or decrease this spacing'by approximately one-thousandth of an inch so that upon rotation of the disc the space will be increased at one port and decreased at the other to create the pressure differential.

The rotor shaft I53 may be connected by a collar I18, Figures '6 and 8 to the disc supporting shaft I19. If the fixed pointer system of communication is used, the movable pointer I is also fixed to shaft I53 for rotation therewith as more particularly shown in Figures 8 and 16. The fixed pointer I8I is secured to an annular flange I82 projecting from the fixed casting I83 of the self-synchronous motor 32. The member I82 has a flanged portion I84 which is suitably graduated for cooperation with a second movable pointer I85 which is fixed to the sleeve I86 carrying the rotatable field of the motor. In this system of operation the pointer I 85 really plays no important part but simply gives an indication to the operator of th actual angular position of the gun.

As previously explained in connection with this system, the pointers I 80 and I'BI must'be maintained in alignment at the gunners station in order to position the gun in accordance with the fire control unit. Therefore after the pointer has been moved upon rotation ofthe rotor 49 by the fire control unit, there must be some form of answer or feed back coming from th gun operating mechanism to tell that the gun has been moved the desired amount andto stop its The two halves are asa r This last I 15 further movement. This is effected in the following manner.

The shaft IOI, which efiects rotation of the pinion 82, has a spur gear I81 connected therewith and intermeshing with a spur gear [88 fixed to shaft I89, the latter being connected by bevel gearing I90 to a shaft I9I which has a worm I92 meshing with a worm wheel I93. The worm wheel I93, as shown in Figure 8, is connected to the sleeve I94 which carries the rotatable field coils suchas 39, 40 and 4|. Thus as the shaft IOI and pinion 82 are rotated, there is a feed back to the self-synchronous motor which continuously rotates the field in the opposite direction to that in which the rotor turned. The rotation of the field in space thus completely neutralizes the advance made by the rotor relative to its field; thus the rotor remains in a substantially fixed position in space as hereinafter described. Thus, if the pointer I80 has been advanced a fraction of a degree and the gun positioned the same amount, the movement of the gun will react to bring this pointer back into alignment with the fixed pointer IBI. In order to understand the principle of operation, it must be kept in mind that the whole chain of events from the fire control unit through the motors, the hydraulic control system, the power unit and the feed back mechanism to worm I93 takes place by minute amounts and almost simultane ously. In other words, as soon as the shaft 26 is rotated the slightest amount, the armature 43 is moved to a new position in relation to its field coils which electrical reaction moves the rotor 49 to the same relative position with respect to its field coils and once this position is established,

the electrical field in the motor is such as to maintain their relative positions so that when the returning answer rotates the worm I93 and thereby the field coil, the rotor 49 will be carried with it as a unit. It will be obvious that the connected shaft I53 and disc I35 will also be rotated a slight amount to set up through the hydraulic relay a rotation of pinion 82 for instance, and that almost simultaneous therewith the feed back or follow-up mechanism will rotate the field a slight amount in the opposite direction, turning the rotor 49 with it to recentralize the disc I35. Thus the disc I35 really need move no more than a fraction of a degree to one side or the other of its center position, and as fast as it is moved the slightest amount by the fire control unit the servo-mechanism will reposition it, or in other words return it to a neutral position. This constitutes the elements of a simple control system.

It will be noted from the previous description that the feed back mechanism to the worm I93 may be connected to the worm shaft I] and not to the pinion rotating shaft 83 which means that the speed of the feed back mechanism would not be reduced by the reduction between the worm I00 and the worm wheel 99 but rather it Was speeded up over the rate of rotation of the drive shaft NH. The actual ratio between the shaft 83 and the worm wheel I93 is usually such that the latter makes one revolution for every ten degrees of angular movement of the turret. This ratio is the controlling factor which determines the number of degrees of angular movement that will be imparted to th gun by each rotation of the rotor 49 relative to its field. Likewise, it determines th angular movement that will be imparted to the gun by one rotation of the shaft 26 since this shaft is connected mechanically and electrically to the rotor 49 in a one to one ratio. It will thus been seen that the ratio of the feed back mechanism determines in the final analysis th amount of angular movement that will be imparted to the gun for one rotation of the shaft 26. If the feed back mechanism is geared to a higher ratio so as to produce a higher speed of the worm gear I93, then the angular movement imparted to the gun by the shaft 26 will be reduced, while if the ratio is stepped down, the angular movement will be increased.

The situation often arises under actual operating conditions that a particular turret may have to be selectively controlled by difierent fire control stations so that if one station is swept away in the stress of battle, another may assume control. This change may be effected by a suitable switch which will disconnect the lines 29', 30' and 3I' from the fire control transmitter 25 and connect them through lines I95, I96 and I91 to a new fire control unit. Since in the case described above, one revolution of the control shaft 26 and its rotor 43 only effects ten degrees of gun movement, it is apparent that any given position of the shaft 25 will correspond to a plurality of gun positions. Thus it might so'happen that the corresponding control shaft and rotor at the new station may have the same operating position relative to its field, as the previous control shaft 26, but may actually be advanced or retracted therefrom by one or more complete revolutions, and therefore no reaction would be set up between the new transmitter rotor and the receiver rotor 49 to correct this situation. It is therefore necessary to provide additional means whereby this contingency cannot occur. It is proposed by this invention to provide a supplemental hydraulic control system which is connected in parallel with the system just described but which is operable for the full 360 degrees so that the transmitter and receiver rotors cannot get out of phase with the gun.

Since as previously described the controlling factor is the ratio of the feed-back mechanism, a second such mechanism is provided which has a one to one ratio with the gun rather than a 36 to 1 ratio as did the previous mechanism, so that the final driven member of this mechanism, such as the worm wheel I98, would be rotated only one revolution by each complete revolution of the gun. This worm wheel is connected to the rotatable field I99 of a self-synchronous motor or receiver 200. This motor has a rotor 20I, one revolution of which relative to its field will correspond to one complete revolution of the gun, because the field I99 is only rotated 'one revolution for each 360 degrees of gun movement. The field I99 is connected by three transmission lines 202, 203 and 204 to the field 205 of a transmitter 206 located at the fire control station adjacent the high speed transmitter 25. The rotor 201 of the transmitter may be connected by the worm wheel 208 and the worm 209 to the control shaft 25 but in a reduction ratio of one to 36 whereby one revolution of the shaft 26 will only effect one thirty-sixth of a revolution of the transmitter rotor 201. It will thus be apparent that the shaft 26 must make 36 revolutions to rotate the transmitter rotor 201 through one revolution which in turn will cause one revolution of the rotor 20I relative to its field. Thus the gun must make one complete revolution in order to cause one revolution of the field I99 and thereby maintain the rotor 20I in a substantially fixed position in space.

The rotor 2M is connected by suitable means, such as the shaft 2), to a second pressure diiferentiator 2H similar to the one previously described, and which is connected by channels 2l2 and 2| 3 to a control valve 2l4 containing a slidable valve plunger 215. This valve has a pressure port 216 which is connected to the pump delivery channel H2 and a pair of ports 2|] and 2l8 which are connected respectively to the lines I 31 and H18 leading to the control motor I32. A spool 219 on the plunger 2l5 determines the alternate connection of ports 2 I1, 218 to the pressure port 2|6. The valve also has another pair of ports 220 and 22! which are connected by branch lines 222 and 223 to the reservoir return line 224. It will thus be seen that this valve plunger operates in the same way as the previously described control valve I39 for alternately connecting pressure .to one of the lines of motor 102 and connecting the other line to reservoir. This valve is also provided with a pressure equilibrator comprising two resistance spools 225 and 226 which are adapted to move relative to the elongated pressure ports 221 and 228 which are connected by branch lines 223 and 230 to the main supply line H2. Each spool carries a reduced portion 23! and 232 which cooperate with these ports to form variable resistances similar to those in valve )9, and thus provide a means for creating a pressure drop in the fluid entering the valve, the fluid escaping freely through axial bores 233 and 234 near the end of the valve, thereby acting upon opposite ends of the plunger to shift the same back and forth when the respective pressures are unbalanced by the pressure difierentiator.

The pressure differentiator disc 235 has a slightly different contour than the previously described disc I35 so that the valve 2M will normally not take control of the motor I02 except in the contingency previously mentioned. When it does take control, however, it is desirable that the previously described ten degree control mechanism be entirely disconnected, .or in other words inoperative to prevent improper operation or loss of fluid pressure through that part of the system. For this reason the pressure supply line H2 to, as Well as the return line 231 from, the valve IE9, is led through the valve 214, so that these lines will be closed when the valve plunger 215 is shifted to a position to control the flow in lines I01 and H18. In other words the return lines I30 and I3! are connected by channel 231 to a port 238 in valve 2M and pressure line H 2 or port 236 of said valve. Each of these ports communicates with narrow annular grooves 239 and 240 respectively formed in the valve plunger 2 45. A second pair of narrow annular grooves 24! and 242 are formed in the plunger 2I5 in spaced relation to the previous grooves but interconnected therewith through equally spaced flats or grooves 243 formed on the periphery of the intervening spools 244 and 245. Each groove 24! and 242 communicates respectively with ports 246 and 241, the port 241 being connected to the pressure line H2 and the port 245 being connected to the return line 224. When the plunger 2 i5 is in a central position as shown in Figure 2 the pressure line H2 is connected to the pressure line I I2 and the return line 231 from valve I09 is connected to the return line 224 thereby permitting the valve plunger IH) to operate in the manner previously described, while ports 21-! and 2l8 are dead-ended so that no flow passes to or from through these ports,

The pressure diiferentiator disc 235 has a port cn of i s c cumf nc ex n ing counter clockwise from th p int 248 to th poin 43 of a radius equal to the distance from the center 2530f the disc 235 to the faces of the ports 1,3 6 and m nus .a very and the included angle .of this are is greater than 1 degrees and may be equal to 185 degrees t per t a two and o hali d c ee verlap at each port. Since the disc I35 does not normally oscillate more than a fraction of a degreefrcm its central pos n w h resp ct to it associated p ts, t will be apparent that dur n orma P- eration of the disc I35 no change in pressure will occur at the ports of disc 235. The remaining p t n of the periphery f the di c .235 extend ing clockwise from the point 248 to the 249 is concentric with the center, but of a radius'which is less by about 2 of an inch, so that when the idiscis rotated a suificieht distance a very sudden decrease in resistance at one of the ports 135i or 131' and thus a sudden drop in'pressiire will occur in one of the channels ,2I2, 2l3'fland thereby insure .a sudden shifting of the valve plungcr 2l5. The formation of the reduced portions 23] and 232 of spools 225 and 226 is such that they effect a small rate of change of hyaulie resistan er un or length of movement of plunger 215 and th y ac sl wly ative to va v plun er movement i i -equ l ing th pressure in channel 1 a d 13 In fa t they are so fo m d t at th plun er will hitth end f v l e us efore r e qual zation of res u e in hannel 2 and 12 13 ccurs. ther y'ihsur ns that the p unge wi l move the hill hsth' its possi e mo ement in ts ho sing nd hu pr vide im e f ll op i or closns i the rious contr l d po t previousl mentioned th s yio ciirs wh n .a con ol stat on which is considerably out of phas w th the gun is onnected therctc, so that a large movement mu t take plac before the parts are brought into proper phase with one another. plunger 254 el her to the right or to the left will cut off the pressure line H 2' and the return lines l3!) and i3] of control valve H3 and immediately connect either line i5? ,or line )8 to pressure through valye 2L4 so that the motor 10.2 Will be at d tc'cau c high speed operation of t e s adjusting motive po r imit- Whil the gun i belngproperly coordinated, the feed back mechasm is p tin o the o m Whe l 1.9.8 a d thereby th ou h the shaft 10,129 r positi n the sc .zes aga n in its normal po n shown n Figure However, due to the fac that he cluded angle of th pe ipheral por ion having the larger radius is be obvious that t e valve 2M w ll nqui h control f re th isc 23.5 has comp c yfreturned whereby the other valv I 09 will again assume o tro to i c th final accurate positioning of the un. a

If the control shaft 26 happens to be d sp ced a ac ion o a revolutio greater than hesha (or any numh r 0f r ol tions plu said f c n) from-the corresponding shaft of the new control station when the atter is connected for opera.-

tion of the gun, the receiverrotor 49 will-attempt to assume itsnew correct position relative .to its field to synchronize with the positionrof the new transmitter. rotor relative to its field by turning .throughtheshortest possible angle which obvi, ously will be in the wrong direction. If permitted to do this, howeventdisc 13 5 would alsoibe turnedv small c ar n e dist nce This sudden [shittin f the valvegreater than degrees, it will in the wrong direction, that is, in the opposite direction to which it should have been turned in order to synchronize the gun with the new control station resulting in the gun itself and also the rotary field 49 being moved in the wrong direction which movement will continue until a position is reached which corresponds to an incorrect displacement of the control shaft 26 equal to the nearest whole number of revolutions greater than the previous fractional displacement. It will thus be seen that in such a case all of the elements of the control system from shaft 26 to and including the valve I59 will be in synchronism with one another but that the gun itself will still be out of phase with the new control station by an angular displacement corresponding to one or more complete revolutions of the transmitter control shaft.

As previously described, however, there is provided a supplemental hydraulic control system including the disc 235 which will assume control whenever the displacement between the new transmitter control shaft and the gun is greater than the overlap of said disc with respect to its ports. This overlap must be made sufiiciently small so that the disc 235 and associated control valve 2I4 will assume control of positioning of the gun whenever the displacement of the control shaft is more than one-half of a revolution with'respect to the corresponding control shaft of the new station, but in order to provide a proper margin of safety, the overlap is actually made substantially less than this.

It will now be apparent that when a new control station is coupled in which is out of phase with the gun in the manner explained that the two discs I and 235 will immediately be moved through large angles whereas small angles of movement will be sufiicient to cause movement of the gun at its highest rate. Therefore in order to prevent too much unnecessary or undesirable movement of the discs, stops 3B6, 301 and 359, 3H1 have been provided on discs 23-5 and I35 respectively which engage opposite sides of fixed pins 358 and 3H to limit the movement.

Attention is invited to the fact that the holes in the bottom of grooves 221, 228, I42 and I43 are all shaped, as shown in Figure 19A, as parallel sided slots 221' with semi-circular ends so that the hydraulic resistance will vary uniformly upon longitudinal movement of the valve plungers.

It will be recalled in connection with Figure 24, that the arcuate shaped passages 13' were alternately subjectible to pressure depending upon the manner of operation of the pump 59. Since the pressure in these passages might become unduly excessive due to sudden movement of the gun at a rapid rate under the abnormal condition previously described, means have been provided for relieving this excessive pressure. A pair of channels 3 I 2 and 3 I 3 are connected to the respective passages as shown in Figure 2 and each has a check valve 3M therein, as shown in Figure 2, set to cause a predetermined pressure drop. These two channels merge into a common channel 3I5 which is connected to one end of a valve housing 3I6 so that the pressure fluid will act on one end of the contained plunger 3I1. An hydraulic resistance coil 3I8 is connected in series between the end of the valve housing and reservoir II I to cause a further pressure drop and thereby maintain a suitable operating pressure on the plunger 3I1. In fact, the value of resistances 3M and 3I8 may be the same whereby half of the pressure drop may occur at each.

The valve housing 3I6 has a pair of longitudinally spaced ports 3I9 and 320 to which the line I08 is connected. Upon movement of the plunger 3I1 against the resistance of spring 32I by excessive pressure in channel 3I5, the spool 322 on plunger 3I1 will close ports 3I9 and 329 and stop operation of motor I02.

A modified form of pressure diiferentiator is shown in Figures 20 and 23, in which the ports I36 and I31 discharge against opposite faces 323 and 324 of the disc 325, an expanded sectional view of which is shown in Figure 23. The dash and dot lines 326 and 321 are degrees apart and the axis of the ports may lie on either one of these lines and thereby normally in the center of the profiled portions 328 and 329 whereby movement of the disc either right or left as viewed in Figure 23 will complementally change the pressure drops at these ports in a manner similar to that described in connection with the profiled portions of disc I35.

In Figures 13 and 14 there is shown a modified form of connecting the feed back mechanism to the pressure diiferentiator. In the prior construction, as described in connection with Figures 2 and 8, the feed back worm I92 acted through the worm wheel I93 to rotate the field in order to maintain the disc I35 in substantially the same position relative to the'opposed ports. This was possible because theelectrical field created in the self-synchronous device was such as to cause the rotor to move simultaneously with the field, the two moving as a unit and therefore rotating the shaft I53 connected to disc I35. It will be seen that the main purpose of this feed back mechanism is to always maintain the disc I35 in substantially the same position at all times with respect to its ports, its total rotary movement normally never exceeding more than a fraction of a degree. In the modified form, shown in Figures 13 and 14, the field 25I is stationary which means that the rotor 252 may be moved continuously in one direction anddikewise the connected differentiator disc 253.

It is desirable, however, to maintain the opposed ports always opposite to the profiled portions I49, I52 and I55, I5I and this may still be accomplished by mountin the ports in a rotatable member 254 and connecting the feed back worm I52 and worm wheel I93 to a reduced portion 255 of this member. In such a case, of course, the channels, such as I38 and I39, shown in Figure 2 must be so connected as to maintain flow through the ports regardless of the angular position of the member 254. To this end the two lines are connected respectively to spaced annular grooves 256 and 251 formed in the hub 255 and connected through interdrillin to a pair of channels 258 and 259, which are connected as before to ports I12. The various connections are diagrammatically illustrated in Figure 14 in which it will be noted that the receiver stator winding is not provided with brushes and collector rings as in the construction shown in Figure 2.

In accordance with the standards of naval authorities of maintaining gun batteries in commission as long as possible, and in spite of various contingencies, there has been provided various alternate controls for utilizing as much of the present equipment that might remain in commission as far as possible. For instance, the communication system from the fire control station to the turret may be intact, but the hydraulic relaysystem from the receiver to the motive power unit may become incapacitated for some reason. Means have been provided, as shown in Figure 2, for utilizing the motive power unit .by controlling the same by hand. To this end the shaft 15 which controls the position of the swash plate is provided with a pinion 260 which is mounted for free rotation on the shaft but may be operatively coupled thereto by a clutch member 26I. This clutch member has clutch teeth 252 on one face engageable with similar clutch teeth 263 on the end of the drive shaft of motor I02 and a, single clutch tooth socket 264 engageable by clutch tooth 265 carried by the pinion. The member 26! is shiftable by a shifter fork 266 pivotally mounted at 261 for operation by the hand lever 268.

It is thus apparent that if the hydraulic control system from the receiver rotor to the motor I02 should become incapacitated, the member I02 may be disconnected from the swash-plate and this plate may be connected to the pinion 260. This pinion meshes with a rack 269 fixed to the end of a longitudinally shiftable rod 210 which is pivotally connected at 21I to one end of a lever 212. This lever is pivoted at a middle point .213 to a fixed part of the turret and has a bifurcated arm 214 engaging a flange 215 formed on the end of shaft 216. This shaft has a threaded portion 211 meshing with a rotatable nut 218 which has a bevel gear 219 surrounding the same and meshing with a bevel gear 280. The bevel gear 280 is secured to one end of a shaft 28I which extends to the gunners position adjacent the gun where it is interconnected through bevel gearing 282 to a manually operable shaft 283. A pair of manual control levers 284 are secured to opposite ends of this shaft, but in 180 degree phase relation to one another for operation by the gunner.

The shaft 216 has a flanged end 285 which has a toothed periphery engaging similar formed internal teeth 283 carried by the tubular member 281. This member has clutch teeth 238 on the one end engageable with clutch teeth 2.80 on the clutch member 129i! which is splined on the end of shaft IBI. The clutch 290 is shifted by the fork 29I which is pivotally mounted at 292 in a fixed part of the turret and operatively connected by a link 293 to the manually operated lever 258.

When it is desired to use the manual control levers 285, the lever 268 is thrown to the left of the position shown in Figure 2, thereby engaging clutch 26d with pinion 250 and clutch 29.0 with the tubular member 281. Upon rotation .of the shaft 283 by levers 284 the nut member 21.8 will be rotated, but since it is held against longitudinal movement by the abutments 294, the shaft 216 will be moved longitudinally instead. As the shaft 216 moves it operates through the link 210 and rack 269 to rotate pinion 299 and thereby angularly position the swash plate .of the power unit which in turn will cause rotation of shaft IM to angularly position the gun. Rotation of the shaft II will, however, through the clutch 290 and the tubular member 281 effect rotation of the shaft 216 in the opposite direction through the member 285. This will cause the shaft 276 to move in the opposite direction from the previous movement imparted by the hand levers and reposition the swash plate to stop power actuation of the gun adjusting mechanism. Since the communication system from the fire control station is assumed to be still in operation the feed back mechanism from shaft IOI will still react on the pointers so that the gunner may still utilize the communication system for determining the position of his guns.

On the other hand, the-communication sys-' tem may be rendered inoperative, inwwhioh case the rotor may .be turned by hand through constead of being connected to the shafti1.5.-is connected to the bevel gearing 282 by means of a bevel gear 295 so that the swash plate is controlled entirely from the rack 269 and pinion 260. In this case the shaft 23I will be moved by the motor, but if the hydraulic system becomesinoperable the device may be controlled manually by the gunner without the necessity of making any changes. However, if the motor IQZ and-the fluid therein does form a drag or resistance to manual operation the fluid therein may be re'' leased to reservoir by providing a suitable .reversing valve 295 having spools for closing off the incoming lines I01 and I08 and connecting theports of motor I02 to-the return line 29 1. This valve may be shifted by the manuallyoperable lever 298 which may be suitably connected to the plunger 299 of the reversing valve. 7

Instead of providing plec1utch- 309 may be provided as shown in Figure 10 between the motor I 02 and the gear 295,

the clutch normally having a position to maintain power operation, but upon downward-movement of the :control lever 30I the clutch may "be disconnected to permit manual operation of the levers 2% without resistance from the motor I02.

There has thus been provided a sensitive controlmechanism which may be connected onthe one hand'to a sensitive communication system and on the other hand to agun adjusting motive power unit for automaticall relaying signals from a remote control station to the power unit without human intervention, together with a suitablefeed back mechanism for limiting and stopping the movement. This mechanismmakes it possiblefor the vessel to directly position, both azimuth and elevation, of'all guns on the ship in an easy and expeditious manner. What is claimed is:

fire control station of a naval 1. In a gun control mechanism the combination of a power unit including a pump and motor, a prime mover for continuously actuating said pump, means coupling the motor to said gun, an oscillatable member for controlling the displacement of said pump, said member having a zero displacement position, a communication system including a transmitter and receiver, means coupling the receiver to said pump. displacement control member including .a fluid rotatable device for moving said member lout of said last .named position upon signal reception from the transmitter to effect actuation of the motor, and means controlled by the .gunfor effecting reverse rotation of said device to move said member into its firstnamed position on compietion by the gun: of .movement .as'determined by the transmitter. f

2.. Ina gun control mechanism the combination of a communication system fortransmitting' the a reversing valve the simand immediately control the" angular extent of gun movement from a remote fire control station to the gun including electrically interconnected self-synchronous devices, one of which constitutes a transmitter at said station, and the other a receiver, said receiver having a, rotor angularly movable in response to signals from the transmitter, a power operable unit connected for gun movement having a control member movable to different positions to start and stop the gun, interponent hydraulic control means for transmitting motion from the receiver to the control member, means operable upon subsequent movement of the gun to move said control member to a stop position, said hydraulic control means including a fluid rotatable motor having a pair of channels connected thereto whereby pressure in either channel, while the other channel is connected to exhaust, will cause reverse rotation of the motor and equal pressure on both channels will stop the motor, and means operable b the receiver for determining pressural flow in said channels.

3. In a gun control mechanism the combination of a transmitter and a receiver, a power operable unit connected to the gun for movement thereof, means controlling the starting and stopping of said unit including a rotary hydraulic motor having a pair of control channels alternately subjectible to pressure to cause reverse operation of said unit, means coupling the motor for control by the receiver including valve means movable to a plurality of positions for determining the channels to be connected to pressure, and means responsive to movement of the gun to position said valve means in a stop position.

4. In a gun control mechanism the combination with a communication system including a transmitter and receiver, of a power operable unit connected to the gun for movement thereof, a rotatable hydraulic motor having a pair of control channels alternately subjectible to pressure for determining reverse operation of said unit, means coupling the channels to said receiver for control thereby including valve means having a neutral position and operative positions on either side thereof, means operable by the receiver upon signal reception from the transmitter to move said valve means to one of its operative positions, and feed back means operative by the gun to move said valve means to its neutral position.

5. In a gun control mechanism the combination with a communication system having a transmitter and a receiver, the receiver including a rotor positionable by the transmitter, a power unit connected to the gun for operation thereof, a

a fluid operable device for controlling actuation of said unit, a pair of channels connected to said device, a source of fluid pressure, a control valve shiftable to difierent positions for alternately connecting said channels to said source of pressure to determine reverse operation of the power unit, and hydraulic relay means responsive to movement of the receiver rotor for shifting said valve to its various positions.

6. In a gun control mechanism the combination with a communication system having a transmitter and a receiver, the receiver including a rotor positionable by the transmitter, a power unit connected to the gun for operation thereof, a device for controlling actuationof said unit including a fluid rotatable motor, a pair of channels connected to said motor, a source of fluid pressure, a control valve shiftable to different positions alternately subjectinglsaid channels to pressure to determine reverse rotation of the 24 motor, relay means responsive to movement of the receiver rotor for shifting said valve to its various positions, and feed back means responsive to gun movement and effective on said motor to move said device to a stop position.

, '7. In a gun control mechanism the combination with a communication system having a transmitter and a receiver, the receiver including a rotor positionable by the transmitter, a power unit connected to the gun for operation thereof, a fluid rotatable device for controlling actuation of said unit, a pair of channel connected to said device, a source of fluid pressure, a control valve shiftable to a multiplicity of positions for alternately subjecting said channels to pressure to determine reverse operation of said device and thereby of said power unit, relay means responsive to movement of the receiver rotor for shifting said valve to its various positions, said relay means including pistons at opposite ends of the valve, and a pressure diiferentiator operable by the rotor for unbalancing the pressure on said pistons to cause shifting of the valve.

8. In a gun control mechanism the combination with a communication system having a transmitter and a receiver, the receiver including a rotor positionable by the transmitter, a power unit connected to the gun for operation thereof, a fluid operable device for controlling actuation of said unit, a pair of channels connected to said device, a source of fluid pressure, a control valve shiftable to different positions for alternately subjecting said ,channels to pressure to determine reverse operation of the power unit, relay means responsive to movement of the receiver rotor for shifting said valve to its various positions, said relay means including pistons at opposite ends of the valve, a pressure differentiator operable by the rotor for unbalancing the pressure on said pistons to cause shifting of the valve, and a pressure equilibrator operable by the valve for re-equalizing the pressure to stop movement of the valve.

9. In a gun control mechanism the combination with a communication system consisting of a transmitter and receiver, of a power operable device connected with the gun for actuation thereof, a power operable control device for starting and stopping said power unit including a pair of channels alternately subjectible to pressure for reverse operation of the power means, a control valve including a shiftable plunger for determining the coupling of pressure to said channels, means coupled to the receiver for shifting said plunger, said plunger having piston portions on opposite ends thereof whereby, when the total pressure on said pistons is unequal, the valve plunger will move, and when the total pressure is equal the plunger will stop, apressure differentiator movable by the receiver for unbalancing said pressure, and an automatic pressure equilibrator for equalizing pressure on said pistons to limit the length of plunger movement.

10. In a gun control mechanism the combination of a power unit coupled to the gun for effecting angular movement thereof, a control member for said unit for determining movement thereof, fluid operable means for shifting said member, a communication system including a receiver unit comprising an integrally movable rotor and pressure differentiator, means coupling said difierentiator to the fluid operable means whereby signals received by said unit will be translated into movement of said control memher, and a pointer associated with said rotor for 25 indicatingthe extent of angular movement effected.

11. A gun control mechanism comprising a power unit for translating the gun, a communication system terminating in a rotor, a pilot control circuit for determining the rate and direction of operation of said power unit including a shif-table control valve plunger, means coupled to the rotor for determining the position of said Plunger including a pressure difierentiator, pistons for shifting said valve means, channels extending from said pistons and terminating in a pair of opposed ports, a disc coupled to the rotor and interposed between said ports, diametrically opposed profiled portions on the periphery of said disc for simultaneously increasing the resistance of one of said ports and decreasing the resistance of the other whereby small angular movements of the rotor and disc will be magnified into large movements of said valve plunger.

12. In a gun control mechanism the combination of a power unit coupled to a gun for oscillation thereof, a communication system terminating in a receiver having a rotor movable in response to signals from a transmitter, interponent power means coupling the rotor for control of the rate and direction of said power unit including a valve plunger having a centra1 inoperative position, and operative positions on opposite sides thereof, a pair of pistons for shifting said plunger, fluid channels extending from said pistons and terminating in opposed ports, a disc rotatably mounted between said ports, said disc having a first position in which the resistance to flow from said ports is equal, portions on the periphery of said disc adaptable upon movement thereof away from its first position to increase the resistance of one port and decrease the resistance of the other, said rotor tending to cause movement of the disc away from its first position to cause actuation of the power unit, and means operable by the gun continuously acting to return the disc to. its first position and thereby automatically stop the movement of the gun.

13. In a gun training and control mechanism the combination of a large power unit coupled to the gun for actuation thereof, a communication system whereby the range of the gun may be transmitted over long distances, said system terminating in a highly sensitive rotor capable of developing a very small power output and a hydraulic amplification system including a valve member integrally connected to the rotor for coupling the rotor to said power unit whereby the small input from said rotor may be amplified to a large output in said power unit.

14. In a gun control mechanism the combination of a communication system including a transmitter and a receiver, a power operable unit for angularly positioning the gun, a pair of relatively separable dials associated with the receiver, one of which is movable relative to the other in response to signals by the transmitter for indicating the extent of gun movement to be effected, means coupling the receiver to the power unit for automatic operation thereof, manually operable means directly connectible with the gun for alternatively translating the same, feed back means operable by the gun for repositioning said dials to indicate that the desired movement has been effected, and selector clutches for coupling either the power unit or said manual means. for control of the gun.

15. In a gun control mechanism the combination with a communicating system having a transmitter and a receiver, said receiver having a pair of dials associated therewitluone of which is movable relative to the other upon signal reception from the transmitter to indicate the extent of gun movement desired, a motive power unit for training the gun, automatic means coupled to the receiver for controlling operation of said power unit, manually operable means for controlling operation of said power unit, a third means including a manually operable device for training said gun independent of the power unit, a feed back system operable by the gun for repositioning the dials to indicate that the; desired extent of gun movement has been completed and selector clutchmeans for coupling any one of said three named means for control of the gun.

16. In a gun control mechanism having a power operable unit for effecting translation of the gun, and a signaling system for transmitting gun ranges from a remote control point including a transmitter and a receiver, the combination of fluid operable means for controlling the rate and direction of said power unit by the receiver including a pair of pressural control channels, valve mechanism operable when a major difference exists between the position of the transmitter and the receiver to effect a sudden pressure differential in said channels and thereby a rapid adjustment of the gun, and additional valve mechanism automatically operable when a minor difiference exists between the transmitter; and receiver variably to control the pressure in said channels in accordance with the relative-displacement in position between the transmitter and receiver.

17. In a gun control mechanism having a power operable unit for effecting translation of the gun, and a signaling system for transmitting gun ranges from a remote control point including a transmitter and a receiver, the combination of fluid operable means for controlling the rate and direction of said power unit by the receiver including a pair of pressural control channels, valve mechanism operable when a major difference exists between the position of the transmitter and the receiver to effect a sudden pressure differential in said channels and thereby a rapid adjustment of the gun, additional valve mechanism automatically operable when a minor difference exists between the transmitter and re.- ceiver variably to control the pressure in said channels in accordance with the relative di placement in position between the transmitter and receiver, a hydraulic couple between said valve mechanisms, said first valve mechanism including a plunger, and meanson said plunger reacting on said hydraulic couple to render said second valve mechanism inoperative during assumption of control by the first plunger.

18. In a gun control mechanism having-a power operable unit connected to the gun for actuation thereof and a communication system including transmitter and receiver rotors, means forcoupling the receiver rotor to said .power operable unit for controlling the rate and direction of movement thereof including a fluid pilot control circuit, a pair of control discs operable by the receiver, valve means associated with the first disc for efiecting large movements of the gun, a second valve means associated with the second disc for effecting minute movements of the gun, and means for rendering the first disc inoperative during assumption of control by the second disc.

19. In a gun control mechanism the combination with a power operable unit connected with a gun for efiecting adjustment thereof, and a communication system including a transmitter rotor and a receiver rotor, the latter being movable in accordance with the movement of the first, of means coupling the receiver to said power operable unit for determining the rate and direction of movement thereof including a fluid operable member, dual control valves coupled in parallel to said member, a source of fluid pressure, hydraulic amplification means between the receiver and each control valve, one of said receivers being unresponsive to small movements of the receiver rotor whereby the other means will assume control of said unit, and means responsive to a large variation in the position of said transmitter and receiver rotors to cause said first named valve means to assume control and render the second valve means inoperative.

20. In a gun control mechanism the combination of a power unit coupled to the gun for effect ing translation thereof, and a communication system including transmitter and receiver rotors angularly positionable to indicate the angular position of the gun, fluid operable control. means for determining the rate and direction of movement of said power unit, a high speed feed back mechanism coupled to the gun whereby one rotation of one receiver rotor will effect only a fraction of a revolution of the gun mechanism, and a low speed feed back mechanism coupled to the gun whereby one rotation of the other receiver rotor will effect one rotation of the gun mechanism for approximate positioning of the gun.

21. In a gun control mechanism the combination of a communication system including a transmitter and a receiver, a powe unit for translating the gun, fluid operable control means between the receiver and said unit for automatically positioning the gun in response to signal reception by the receiver, relatively separable pointers associated with the receiver for indicating the amount of movement imparted to the gun, manually operable control means for effecting operation of said power unit, feed back means operable by the gun to re-align said pointers to indicate that the desired movement of the gun has been completed regardless of whether the movement has been effected automatically or manually, said feed back mechanism also acting to automatically stop the gun movement upon re-alignment of said pointers when automatically controlled, an additional feed back mechanism for terminating movement of the gun when the same is manually controlled, and a manually operable control valve for rendering the first system inefiective during operation of said manual control means,

22. A gun control mechanism comprising a power unit for translating the gun, a communication system terminating in a rotor, a pilot control circuit for determining the rate and direction of operation of said power unit including a shiftable control valve plunger, means coupled to the rotor for determining the position of said plunger including a pressure difierentiator, pistons for shifting said valve means, channels extending from said pistons and terminating in a pair of opposed ports, a disc coupled to the rotor and interposed between said ports, profiled portions on said disc for simultaneously increasing the resistance of one of said ports and decreasing the resistance of the other whereby small angular movements of the rotor and disc will be magnified into large movements of said valve plunger.

23. In a gun'control mechanism thecombina tion of a power unit coupled to a gun for oscillation thereof, a communication system terminating in a receiver having a rotor movable in response to signals from a transmitter, interponent power means coupling the rotor for control of the rate and direction of said power unit including a valve plunger having a central inoperative position, and operative positions on opposite sides thereof, a pair of pistons for shifting said plunger, fluid channels extending from said pistons and terminating in a pair of ports, a disc rotatably mounted for movement past said ports, said disc havinga first position in which the resistance to flow lrom said ports is equal, profiled surfaces on said disc adaptable upon movement thereof away from its first position to increase the resistance of one port and decrease the resistance of the other, said rotor tending to cause movement of the disc away from its first position to cause actuation of the power unit, and means operable by the gun continuously acting to return the disc to its first position and thereby automatically stop the movement of the gun.

24. In a gun control mechanism, the combination with a synchronously inter-connected transmitter and receiver, of a variable speed power unit for effecting movement of the gun, a rotary hydraulic motor connected to the unit and adjustable to determine the direction and rate of operation of said unit, interponent hydraulic means for translating movement of the receiver into fluid actuation of the motor, and means responsive to movement of the gun and effective on said interponent hydraulic means to stop said power unit.

25. In a gun control mechanism, the combination of a transmitter and a receiver, a variable speed power operable unit connected for moving the gun, said unit having an oscillatable rate control member movable in opposite directions from a stop position to accelerate said unit, a rotatable fluid operable motor for power moving said rate control having a pair of control channels selectively subjectable to pressure to cause reverse operation of the motor, valve means coupling the channels for control by th receiver whereby movement of the receiver will shift said valve means to cause acceleration of the power unit, and means responsive to movement of the gun for repositioning the valve means to reverse the pressure connections to said channels and thereby stop the power unit.

26. In a gun control mechanism the combination with a synchronously interconnected transmitter and receiver, of a power operable unit connected to the gun, said unit having an oscillatable rate and direction control member, a rotatable fluid operable motor for oscillating said member, a pair of control channels selectively 'sub- J'ectable to pressure for delivering fluid to said motor, means coupling the channels to the re-- ceiver for control thereby including valve means having a neutral position, and operative positions on either side thereof, means responsive to movement of the receiver for shifting said valve means to one of its operative positions, and feed back means operative by the gun to move said valve means to its neutral position.

27. In a gun control mechanism the combination with a synchronously interconnected transmitter and receiver, said receiver including a sensitive rotor positionable by the transmitter, of a variable speed power unit connected for operation of the gun, said unit having an oscih 

